Using Replica Role Promotion

Directory Server includes a way of promoting and demoting the replica
role of a directory instance. This feature enables you to promote a replica
hub to a multi-master supplier or vice versa. You can also promote a consumer
to the role of replica hub and vice versa. However, you cannot promote a consumer
directly to a multi-master supplier or vice versa. In this case, the consumer
must first become a replica hub and then it can be promoted from a hub to
a multi-master replica. The same is true in the reverse direction.

Replica role promotion is useful in distributed deployments. Consider
the case when you have six geographically dispersed sites. You would like
to have a multi-master supplier at each site but are limited to only one per
site for up to four sites. If you put at least one hub at each of the other
two sites, you could promote them if one of the other multi-master suppliers
is taken offline or decommissioned for some reason.